window.onscroll = function (e) {
	addBox();
};

function addBox() {
	let boxes = document.querySelectorAll(".box");
	let windowHeight = window.innerHeight;
	boxes.forEach((box) => {
		let boxTop = box.getBoundingClientRect().top;
		if (boxTop < (windowHeight / 5) * 4) {
			box.classList.add("show");
		} else {
			box.classList.remove("show");
		}
	});
}
